Quote:
Originally Posted by Daox
I was also surprised by the lack of windows. Probably mostly due to the cost.
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From the description of the builder's chain of decisions, I think that it is a very good bet that he is using the Passive House Planning Package.
With PHPP, you can instantly see the thermal consequences of your decisions.
If I'm not mistaken, there may be a version of PHPP that will also allow you to do cost estimations at the same time.
But there is no "prettiness" calculator built in.
Regarding the resistance heater, I think he went for that because it is cheap and reliable, but inefficient. At $80 cost, not a bad decision... too bad he doesn't report resistance heating cost info.
But a very small mini-split would be much more efficient, and would be within the output rate of his PVs by a larger margin.
I just did a hasty break-even analysis, based on the scarce information available. "X-axis" is years to break-even. "Y-axis" is annual electric cost (as if it came from a power company).
If his power requirement for heating is very, very low (as it should be), the time to break even would be discouragingly long. So, my guess is that his decision was not motivated by cost and pay-back considerations, but rather he opted for the mini-split so that he could enjoy additional electrical loads and still be within his Net Zero goal.
-AC